Method of casting metal



CRGSS REFERENCE CHARLES MGKNIGHT, JR, OF SEWICKLEY, PENNSYLVANIA.

METHOD OF CAS'IIN METAL,

No Drawing.

To all whom it may concern:

Be it known that I, Cnanms MoKmerrr,

Jr., a citizen of the United States, residing at Sewickley, in the county of Allegheny and State of Pennsylvania, have invented new and useful Im rovements in Methods of Casting Metal, 0 which the following is a s ification. I

y invention relates to the art of casting iron and steel roducts, whether in their initial, final or intermediate state of manufacture. I

v The objects thereof are to reduce porosity, such as blOWvhOlGS, and remove ox1d inclusions at or near the surfaces of cast ferrous articles, to improve the surfaces of such articles, and to facilitate the removal of the articles from their molds. 4

-For the urposes of illustration merely, I will describe my invention as practised in the production of steel ingots in steel or cast-iron molds, but it is to be understood that I do not limit my invention to the production of any definite article or to the casting of any definite metal, or to the use of any type of mold, for it may be applied to the casting of any iron or steel article in any mold, whether composed of iron, steel, molding sand, or other material. I It is applicable to the surfaces of cores as well as to the surfaces which form the outer walls of the cast articles.

Hitherto the surfaces of ingots where they contacted, with the molds have contained holes .formed by 'gas entrapped orconfined in the ingots at or near their surfaces- After rollin the ingots,these holes, commonly called bfiiw-holes, result in various defects, such as seams, .s'ponginess, or cracks, which have to be chiseled or otherwise cut or removed. The removal of blowholes or other porosity is a very expensive operation and causes much delay in the manufacture of the ultimate product. By

the present invention, I prevent or, at least,

lessen the formation of blow-holes, improve the surfaces of the cast articles and facilitate their removal from their molds.- By this invention I also reduce metallic oxids which may be included in the metal.

I prevent or lessen the formation of blowholes and the inclusion of metal oxids by appl to the article-forming surfaces of the mol with the metallic oxids and the gases tending to form blow holes. This agent may be oneor 'a suitable agent whlch combines a more of several substances, such as aluminum, titanium, magnesium, or other uivalents. I regard the application to mo ds of any agent capable o combinin with the sea which tend to form blow-ho es as coming within my invention, no matter what materials compose the molds or the articles 'cast. I have found powdered aluminum to be a very satisfactory ent. It may be applled in a dry condition y blowing or dustm it on the mold surfaces. I may mix it with various dilutents, or carriers, as molassesor water or colloidal solutions, for exam 1e, and apply the resultant composition wit a brush, a spraying nozzle, or" other device. I find that, by employing a colloid, preferably in solution with water, as my EXAMIN sp ifi oil-cite" Patented Feb. 24, 1920. Application filed December suppers. semi llo. uaaoe.

carrier for the aluminum, the aluminum is held in suspension indefinitely which facilitates its application to the mold. As examples of such colloids I cite the following: glue, starch, sodium silicate, tannic acid, extrose, and gelatin. I may employ in addition to the said agent, a umm or its equivalent, a substance, such as graphite, to lubricate the mold and prevent the sticking of the article therein. Graphite serves to give more body to the composition and enables it to spread more and cover a larger surface. The glraphite may be a plied separate] or wit one or more 0 the other ingr ients. I may apply silica wash or slaked lime to the mold either. separately or mixed with one or more of the other dients to prevent the sticking of the article in the mold. As examples of the composition which I have found satisfactory I give the following: first, two fgallons of sodium silicate, fifty pounds 0 wdered aluminum, twenty pounds of gra ite, and water sufiicient to make about fi y gallons of the'mixture;. second, one pint of molasses, two pounds of powdered graphite, one und of powdered aluminum and water su cient to make about two gallons of the mixture.

While I have given various illustrations of com sitions containing'one or more gascom ining and reducing agents, and of used with one or more of such agents without first forming compositions t rewith, I wish it to be understood that these illustrations are merely examples of the many means and methods by which my invention may beractised. In applying my coating to molding surfaces, I use substantially the amount needed to cause the removal of included oxids and gases, and not enough to materially alter the physical characterlstics of the metal. By physical characteristics I mean hardness, ductility, and tensile strength and the like. I am not attempting to form' a coat of aluminum or other material on castings; I employ as much 'alum1 num or its equivalent as is requined'to combine with the gases which tend to form blow-holes.-

This application is a continuation in part of my application, Serial Number 323,926, filed September 15, 1919.

claim: 1. The method of reducing porosity and lessening included metal-oxids at or near the surface of ferrous castings which consists in applyinglto the molding surface a metalliccoatin aving the propert of combining with the gases and oxids in t e molten metal and then running molten metal into the mold, said coating containing substantially the amount needed to cause the removal of the occluded gases and the oxids and not enough to materially alter the physical properties of the metal.

3. The method of reducing porosity and lessening included metal-oxids at or near the surface of ferrous castings which consists in applying to the molding surface a coating havin the property of chemicall combining with the gases and oxids in t e molten phzsical properties of the metal. porosity and lessening included metal-oxi s at or near the metal and then running the molten metal into the mold, said coatmg containing substantially the amount needed to cause the removalof the occluded gases and the oxids and not enough to materially alterthe The method of reducing surface of ferrous castings which consists in ,applyinglto the molding surface a metallic coating ses-and the oxids and 5. The method ofreducing porosity at or 7 near the surface of ferrous castings which consists in a plying to the molding surface a coating 0 powdered aluminum 'and then running the molten metal into the mold.

6. The method of reducing porosity at or near the surface of ferrous castings which consists in applying to the molding surface a coating of powdered aluminum together with a suitable carrier and then running the molten metal into the mold.

7. The method of reducing porosity at or near the surface of ferrous castings which consists in a plying to the molding surface a coating 0 powdered aluminum to ether with a suitable carrier, containing a co oidal substance, and then running the molten metal into the mold.

8. The method of reducing porosityat or near the surface of ferrous castings which consists in applying to the molding surface a coating of powdered aluminum with graphite and a suitable carrier and then runnin the molten metal into the mold.

Signed at Pittsburgh, Pa., this 18th day of December, 1919.

CHARLES McKNIGHT, JR. 

